You can milk the dog's prostate like the urologist milks men's prostates to relieve the fluid congestion. You need some rubber gloves and a lubricant like K-Y Jelly. Put the glove on, lube up your index finger and stick it up your dog's butt. With your palm facing down, push your finger down onto the dog's prostate and apply steady, firm pressure. You should see a clear discharge from the dog's penis. This is the congested prostatic fluid being released. This should be repeated once a week until your dog's enlarged prostate returns to a normal size. You may have to resume this treatment after some weeks or months.